Apump is driven by a 2-kw motor with water at 150 kpa, 10 cesius entering. find the maximum water flow rate you can get with an exit pressure of 1 mpa and negligible kinetic energies. the exit flow goes through a small hole in a spray nozzle out to the atmosphere at 100 kpa. find the spray velocity.

42.4m/s

Explanation:

To develop the problem it is necessary to apply the concepts related to thermodynamic work and Bernoulli's principle in which the behavior is described of a liquid moving along a stream.

The work of an incomprehensible liquid is given by the equation,

Where,

= Mass flow

= Specific Volumen

P = Pressure

Our values are given by,

= 2kW

Table 1 for saturated water in 10°C

We need to find the mass flow, then re-arrange for

To find the Spray velocity, we apply Bernoulli equation, because at the Nozzle there is not Work or Heat transfer related. Then,

Therefore the spray velocity is 42.4m/s

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.